The role of suggested size in distance responses

A number of studies have concluded that suggested size can modify perceived size, as indicated by the effect on perceived distance. At least this effect seems to occur when verbal reports are used as the measure of the judged distance of the target. The present study supports a different explanation of this phenomenon. It is hypothesized that suggested size can result in the judgment that the target is larger or smaller than normal (an off-sized judgment) where normal is specified by the suggested size. Because the observer expects that a target judged as a small or large off-sized object must be at a greater or lesser distance, respectively. than its perceived distance, the off-sized judgment can provide a cognitive modification of reported distance. This explanation was tested by measuring the perceived distance of targets using a procedure (called the head motion procedure) that, in contrast with verbal reports of distance, is very unlikely to be influenced by off-sized judgments. Measures obtained with the head motion procedure, unlike those obtained from verbal reports, did not change with changes in the suggested size. It is concluded that the size suggestions had a cognitive, not a perceptual, effect on responses to the distance (and size) of the targets.

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